Background Recurarization has previously been described in the context of acute normovolemic hemodilution.The aim of this study was to investigate the impairment of recovery of neuromuscular function after re-transfusion of intraoperative salvaged blood in patients treated with rocuronium.Methods We enrolled 50 patients undergoing general anesthesia for lumbar surgery.Intraoperative blood salvage (IBS) was used in 30 patients (group Ⅰ); the remaining 20 comprised a control group (group C).Anesthesia was induced with fentanyl,midazolam,propofol and rocuronium.Rocuronium was infused to maintain neuromuscular blockade during surgery.Blood was collected from the operative field and re-transfused in the post-anesthesia care unit (PACU).Neuromuscular function was monitored using the train-of-four ratio (TOFr).Once the train-of-four ratio exceeded 90 in the PACU,neuromuscular function was evaluated every 5 minutes for 30 minutes.The TOFr and incremental recovery of TOFr from baseline were recorded.Salvaged blood was re-transfused at the beginning of the evaluation for patients in group Ⅰ,and afterwards for patients in group C.Blood gas analysis was assessed before anesthesia and in the PACU.Results Incremental recovery of TOFr from baseline was significantly less in group Ⅰ than controls at 25 minutes (6.1±3.2vs.9.1±3.2,respectively; P=0.001) and 30 minutes (7.1±3.2 vs.10.0±2.2,respectively; P=-0.001).There were no significant differences in gas exchange between the groups.Conclusions In patients who had received a rocuronium infusion during anesthesia,re-transfusion of salvaged blood significantly impaired recovery of neuromuscular function recovery in the PACU,but without significant impairment of respiratory function.